as A is to B, so is C to D;
or A is to B, as C is to D.
ſignifies parallel to.
. . . . . . perpendicular to.
. . . . . . angle.
. . . . . right angle.
. . . two right angles.
or 
briefly deſignates a point.
or ſignifies greater, equal, or leſs than.
The ſquare deſcribed on a line is conciſely written thus, 2.
In the ſame manner twice the ſquare of, is expreſſed by 2 . 2.
def. ſignifies definition.
pos. . . . . . . poſtulate.
ax. . . . . . . . axiom.
hyp. . . . . . . hypotheſis. It may be neceſſary here to remark, that the hypotheſis is the condition aſſumed or taken for granted. Thus, the hypotheſis of the propoſition given in the Introduction, is that the triangle is isoſceles, or that its legs are equal.
const. . . . . conſtruƈtion. The conſtruƈtion is the change made in the original figure, by drawing lines, making angles, deſcribing circles, &c. in order to adapt it to the argument of the demonstration or the ſolution of the problem. The conditions under which these changes are made, are as indiſputable as those contained in the hypotheſis. For inſtance, if we make an angle equal to a given angle, these two angles are equal by conſtruƈtion.
Q.E.D. . . . . Quod erat demonſtrandum.
Which was to be demonſtrated.
